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-   -   Cylinder 7 missfire. (http://www.f150forum.com/f6/cylinder-7-missfire-226253/)

Jacob.P93 09-09-2013 11:57 PM

Cylinder 7 missfire.
 
I have an 01 w/144k cylinder seven is missing I've swapped cops and plugs with cylinder 1 and it's still missing on 7. Ive checked the injectors and they are working. And just the driver side cat gets glowing red. It idles rough but I assume it's the missfire I've checked for vacuum leaks and found none I've check to make sure everything is plugged in. I cleaned the maf I'm kinda at a loss. Let the ideas fly!!! I've got an ase certified chevy mechanic as a nieghbor and he can help me do whatever. Tomorrow we are gonna check compression.

primalurges 09-10-2013 12:12 AM

If your manifold is glowing red your cat is toast. For what ever reason seven is getting hot first and preigniting fuel giving you the misfire.

Jacob.P93 09-10-2013 12:39 AM

Quote:

Originally Posted by primalurges (Post 2962825)
If your manifold is glowing red your cat is toast. For what ever reason seven is getting hot first and preigniting fuel giving you the misfire.

Do you know where to look to find the reason? And I plan on removing them.

primalurges 09-10-2013 07:01 AM

Quote:

Originally Posted by Jacob.P93 (Post 2962874)

Do you know where to look to find the reason? And I plan on removing them.

As far as the cause is concerned it is usually an unattended misfire or running too rich. If you have very high mileage I suppose they may just eventually fail. The computer may sometimes indicate that there is insufficient exhaust flow but computer will not always point you straight to the problem. I remember you mentioned rough idle but are you havi g rough operation also while driving? Any loss of power?

Jacob.P93 09-10-2013 08:30 AM

Quote:

Originally Posted by primalurges (Post 2963054)
As far as the cause is concerned it is usually an unattended misfire or running too rich. If you have very high mileage I suppose they may just eventually fail. The computer may sometimes indicate that there is insufficient exhaust flow but computer will not always point you straight to the problem. I remember you mentioned rough idle but are you havi g rough operation also while driving? Any loss of power?

Yes a ton of loss power and she drives decent just no power.

primalurges 09-10-2013 08:44 AM

Quote:

Originally Posted by Jacob.P93 (Post 2963128)

Yes a ton of loss power and she drives decent just no power.

Yeah you've got a clogged cat. You should also address the underlying issue that caused the damage. Likely bad plugs and/ or coils.

Jacob.P93 09-10-2013 12:38 PM

Quote:

Originally Posted by primalurges (Post 2963147)
Yeah you've got a clogged cat. You should also address the underlying issue that caused the damage. Likely bad plugs and/ or coils.

Well I've checked coils and plugs and their throwing a good spark. I swapped everything with cylinder 1 but the missfire stayed on 7. A clogged cat can cause a missfire? I had a vacuum leak but fixed that and that cleared it up a lot cause before the leak I was running on 3 cylinders. Now the leak is fixed and it's just a miss on 7. And I was hunting for the leak for a while. Was driving and she completely died and was misfiring on 5 cylinders and no power what so ever. fixed the vac leak and cleared everything but the no power and miss on 7

primalurges 09-10-2013 02:54 PM

The function of fuel in a combustion chamber is to produce power and cool the piston that's why it is so detrimental for an engine to run lean. With a clogged cat the piston can't be cooled enough by its required level fuel and can pre-ignite causing detonation. Popping is usually unburned fuel hitting jot surface like an exhausts manifold and igniting in there instead of combustion chamber. I don't see how anything but a clogged cat can cause your manifold to glow. A cat should be one of the easiest parts in your car to diagnose once its been removed. And all the misfiring you were experiencing from your lean condition may have damaged your cat. We're most of the misfires you ha previously on the same side of the engine as #7?

Jacob.P93 09-10-2013 03:27 PM

Quote:

Originally Posted by primalurges (Post 2963850)
The function of fuel in a combustion chamber is to produce power and cool the piston that's why it is so detrimental for an engine to run lean. With a clogged cat the piston can't be cooled enough by its required level fuel and can pre-ignite causing detonation. Popping is usually unburned fuel hitting jot surface like an exhausts manifold and igniting in there instead of combustion chamber. I don't see how anything but a clogged cat can cause your manifold to glow. A cat should be one of the easiest parts in your car to diagnose once its been removed. And all the misfiring you were experiencing from your lean condition may have damaged your cat. We're most of the misfires you ha previously on the same side of the engine as #7?

Yes all but 8 were missing on that bank and an 3-4 were missing in the other bank. And we were gonna throw a gauge in the o2 to check how much pressure is building before the cat. But the o2 was froze in. I put some pb blaster and kroil on it so maybe we can get it tonight.

primalurges 09-10-2013 04:15 PM

Quote:

Originally Posted by Jacob.P93 (Post 2963904)

Yes all but 8 were missing on that bank and an 3-4 were missing in the other bank. And we were gonna throw a gauge in the o2 to check how much pressure is building before the cat. But the o2 was froze in. I put some pb blaster and kroil on it so maybe we can get it tonight.

That's an interesting approach to testing cat. Good luck busting that sensor loose, based on your description of the manifold it's probably welded itself in place. Keep us updates.


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